As a catalyst substituted for Ziegler-Natta catalysts which have been used in the polymerization of olefins, a part of the metallocene compounds is being used which consist of a complex compound wherein a multidentate compound containing a i-electron donor such as unsubstituted or substituted cycloalkadienyl groups is coordinated to a transition metal atom, the unsubstituted or substituted cycloalkadienyl groups including e.g., unsubstituted or substituted cyclopentadienyl groups, unsubstituted or substituted indenyl groups, unsubstituted or substituted tetrahydroindenyl groups, and unsubstituted or substituted fluorenyl groups.
In recent years, various metallocene compounds have been proposed having higher olefin polymerization activity per mole of a transition metal atom. It is known that the polymers of .alpha.-olefin having 3 or more carbon atoms, in particular, propylene polymers, prepared by using a chiral metallocene compound have high stereoregularity, the chiral metallocene compound being the compound wherein a multidentate compound having two substituted cycloalkadienyl groups bonded with a divalent linking group is coordinated to a transition metal atom (J. Am. Chem. Soc. 1998, 120, 11316-11322).
Further, the development of metallocene compounds with high olefin polymerization activity has continued. Various metallocene compounds have been proposed wherein a heteroatom is introduced into the substituent or cycloalkadiene ring in the substituted cycloalkadienyl group.
For instance, Japanese Patent Kokai 7-258282 discloses metallocene compounds wherein the 2-position of the indenyl group is substituted by a saturated group containing a heteroatom such as nitrogen, phosphorus, arsenic, antimony, bismuth or the like, specifically those wherein 2-pyrrolidino-1-indene is linked through a divalent linking group and coordinated to a transition metal atom.
Japanese Patent Kokai 8-183814 discloses chiral metallocene compounds wherein the 4-position of the indenyl group is substituted by unsubstituted or substituted 1-pyrrolyl group, 1-indolyl group or the like, specifically those wherein 4-(1-indolyl)-2-methylindene is linked through a divalent linking group and coordinated to a transition metal atom.
J. Am. Chem. Soc. 1998, 120, 10786-10787 discloses metallocene compounds wherein a heteroatom-containing cycloalkadiene having a thiophene ring or a pyrrol ring condensed to a cyclopentadiene ring is linked through a divalent linking group and coordinated to a transition metal atom.